Intravenous or intra-arterial administration of liquids, such as oncotherapeutic drugs, commonly use a hollow needle or catheter inserted into a superficial artery or vein. However, patient movements may dislodge the needle/catheter from the vein or artery permitting an accumulation of liquid in the perivascular tissue with concomitant discoloration, discomfort, and possibly extensive destruction of tissue. Presently, detection of this condition requires sufficient infiltration of liquid to produce pain, swelling, discoloration or cessation of liquid administration due to the buildup of liquid pressure within the local tissues. The Phase I Study proved the feasibility of passive, noninvasive microwave radiometry for the early detection of extravasation. Data indicates that the detectability of extravasation increases with flow rate, with difficulty experienced at flow rates less than 20 ml/hour with room temperature fluids. Also, the detectability increases as fluid temperature decreases and detectability appears independent of the diameter of the IV cannula. The proposed program, taking full advantage of the positive results of the Phase I Study and consistent with objectives provided by the health care industry, will lead to the development and a of extravasation. Antenna configurations evaluated in Phase I indicated feasibility of a disposable low cost conformal printed circuit antenna. The development of this antenna will also be completed in Phase II.